Femobook A4Z Electric Grinder Review | French Brewers Cup Champion Cha

【Who Is Charity?——From Home Roasting to French Brewers Cup Champion】

Charity’s coffee journey began five years ago. At the time, she says she “simply liked to drink a good cup of coffee,” and never imagined she would one day step into the industry.

During the pandemic lockdown, she and her partner started roasting coffee in France’s Champagne region and selling it online. What began as a hobby gradually grew into a profession.

In her first competition in 2021, she went over time. Just a year later, she came back to win the 2022 French Brewers Cup Championship, and she claimed the title again in 2024. These experiences brought her onto the world stage, where she continues to share competition insights in her everyday brewing.

At World of Coffee, one of the industry’s biggest events, Charity invited the audience to taste side by side and discover how a single grind adjustment could change the flavor of a cup.

【Compact and Convenient: Type-C Charging and Magnetic Receiver】

Charity mentioned that the Femobook A4Z is her “favorite grinder.” She brews with it almost every morning and only needs to recharge about once every three weeks [1]. And the grinder comes with a Type-C charging port [2].

She also pointed out other practical features during her presentation: a magnetic grounds receiver for quick handling, and a total weight of around 2 kilograms (about 4.4 lbs), making the grinder compact and lightweight.

Frank

Femobook's Editor

1. The A4Z is powered by a 6000mAh battery module. A full charge provides about 30–60 grinding sessions (based on 20g of beans per use). Since the battery pack is user-replaceable and rechargeable, you only need to swap the cells when capacity declines—instead of discarding the entire grinder—making it both cost-effective and environmentally friendly.

2. The Type-C port also supports charging via a power bank, so whether you’re outdoors, camping, or at a gathering, the grinder can be recharged anytime and anywhere.

【A4Z vs. ZP6: Two Distinct Flavor Profiles】

During her presentation, Charity shared that she usually carries the 1Zpresso ZP6 when traveling, while at home she brews with the Femobook A4Z  [1].

She once compared the A4Z and the ZP6 in a blind tasting and found that each produced a distinct cup profile. In her experience, the ZP6 tends toward a more balanced profile, whereas the A4Z delivers greater clarity—especially when brewing washed Ethiopian coffees, where its clean expression really stands out.

Frank

Femobook's Editor

1. The Femobook A4Z is equipped with the ZP6 burr set, licensed from 1Zpresso. Originally developed for pour-over brewing, the ZP6 is highly regarded for producing a clean cup with well-defined layers. It was also the hand grinder used on stage by Carlos Medina, the 2023 World Brewers Cup Champion.

【Minimal Fines, Clean Flavor, and a Smooth Finish】

During the presentation, Charity highlighted another advantage of the Femobook A4Z: it noticeably reduces the dryness in the aftertaste.

She explained that the grinder generates minimal fines, and when used with the right water, the resulting brew is cleaner and delivers a smooth, pleasant finish without dryness.

【How Grind Sizes Affect Clarity, Acidity, Sweetness, and Balance】

One key insight Charity gained from competition is that grind size often has a bigger impact on flavor than other variables. She explained it this way during her presentation:

“You can change your temperature, you can change your recipe, you can change your dripper, but it's not gonna make a big difference if you don't have a good grinder or if you're using the same grind setting.”

— Charity Cheung, French Brewers Cup Champion 2022 & 2024

She noted that the Femobook A4Z offers over 300 grind settings, with steps as fine as 0.008 mm. In her demonstration, she used two different coffee beans and brewed them three times, making slight adjustments in grind size.

In the first two brews, grind size was the only variable, allowing the audience to observe how flavor shifted with grind alone.

Frank

Femobook's Editor

1. The A4Z features micrometric grind adjustment with over 300 settings (0.008 mm per step), helping brewers easily find the sweet spot for each coffee and unlock its delicate flavor layers. With minimal fines and consistent, stable grind performance, the A4Z also ensures those flavors can be reliably reproduced once the sweet spot is discovered.

First Brew: A4Z at Setting 153 – Clean Cup with a Lingering Finish

Charity first demonstrated a brew at setting 153 on the A4Z, using 16g of washed Ethiopian coffee with the Hario Mugen Switch dripper at 91 °C.

Her method was a two-stage immersion: with the valve closed, she poured 50g of water to bloom the grounds and let it sit for 30 seconds. She then added water up to 215g, keeping it fully immersed. At 2:05, she opened the valve to let the coffee draw down.

Tasting Notes：Jasmine aroma with sweet lemon notes and a long finish. 

Charity found the cup already quite clean, but noted that coarsening the grind slightly could bring even greater clarity.

Second Brew: A4Z at Setting 159 – Greater Clarity in the Cup

For the second brew, the only variable changed was the grind size—moving the A4Z from setting 153 to 159.

Charity invited the audience to taste both cups side by side and experience how just six clicks can make the cup taste different.

Parameters

• Coffee: 16g, washed Ethiopia

• Water: 215g at 91 °C

• Grinder: Femobook A4Z, setting 159 (the only variable)

Pouring

• 00:00 → valve closed, pour to 50g for bloom

• 00:30 → valve closed, pour to 215g for immersion

• 02:05 → release the valve to draw down

Tasting Notes：The 2nd brew showed greater clarity, with bergamot and tropical fruit notes emerging, balanced by a sweetness of brown sugar.

Third Brew: A4Z at Setting 162 – Highlighting Sweetness in Kenyan Coffee for Better Balance

For the third brew, Charity chose a Kenyan coffee—one she doesn’t usually like because it often shows tomato-like notes, too much acidity, or floral tones without enough sweetness.

But she found the A4Z changed her perception: “This grinder really highlights the sweetness in Kenyan coffee, making the overall cup more balanced.”

Parameters

• Coffee: 17g, Kenyan AA, washed

• Water: 215g at 91 °C

• Grinder: Femobook A4Z, setting 162

Pouring

• 00:00 → valve closed, pour 50g, gently swirl the dripper, full immersion bloom

• 00:30 → open the valve to release liquid

• 00:45 → pour to 215g with a continuous pour, keeping the valve open

• Final stage → close the valve to control the finish, then remove the dripper

Tasting Notes：Charity pointed out that when using the A4Z, Kenyan coffees showed characteristics different from what she usually experienced. The typical tomato-like note or excessive acidity was balanced by a brown sugar sweetness, resulting in a more harmonious overall profile.

【Brewing Recipes from French Brewers Cup Champion Charity】

Pour-Over Recipe 1

Method

• 00:00 → valve closed, pour 50g of water and bloom for 30 seconds

• 00:30 → keep valve closed, pour to 215g for full immersion

• 02:05 → open the valve to let the brew draw down

Pour-Over Recipe 2

Method

• 00:00 → valve closed, pour 50g, gently swirl the dripper, bloom in full immersion
  

• 00:30 → open the valve to release liquid
  

• 00:45 → keep the valve open, pour to 215g with a continuous pour
  

• Final stage → close the valve to control the finish, then remove the dripper

【Charity’s Take on the Femobook A4Z】

Charity shared her appreciation for the Femobook A4Z, calling it her “favorite grinder” and noting that it is especially well-suited for home use. She highlighted that the grinder is easy to use, lightweight, and has strong battery life.

She emphasized that the A4Z makes it possible to brew coffee with exceptional clarity and a well-balanced cup profile. By producing minimal fines, it eliminates dryness in the finish and delivers a smooth mouthfeel.

According to Charity, the A4Z excels with washed Ethiopian coffees, bringing out remarkable clarity, while with Kenyan coffees it highlights sweetness that balances their often-excessive acidity.

Note: The content above is excerpted from the YouTube video by《Femobook》.